Typically, a pneumatic tire has a tread portion provided with a circumferentially and continuously extending main groove, and a plurality of lateral grooves communicated with the main groove. Such a pneumatic tire produces air column resonance noise from the main groove during traveling and it reaches outside a vehicle through the lateral grooves. Conventionally, in order to reduce such noise generated from the pneumatic tire, a lateral groove including a small-width part is proposed. The lateral groove with the small-width part may help to reduce the noise by disturbing the air column resonance.
Unfortunately, since the small-width part of the lateral groove may increase drainage resistance, the tire is liable to deteriorate its drainage performance.